With age a large percentage of the population develops atherosclerotic arterial obstructions resulting in a diminished blood circulation. The disturbance to blood flow that these obstructions cause may induce blood clots which further diminish or block the blood flow. When this process occurs in the coronary arteries it is referred to as a heart attack. Presently such obstructions are circumvented by surgically grafting a bypass or they are treated by a catheter equipped with a balloon which is inserted through the arterial system, over a flexible guide-wire, into the obstruction and then inflated to expand the obstruction's lumen (angioplasty). Some of the problems with angioplasty are that it injures the arterial wall, it creates a rough lumen and in substantial number of the cases it is ineffective. Further, angioplasty does not remove the obstruction material out of the arterial system, therefor in a case of a heart attack, immediate angioplasty carries the risk of dislodging the blood clot and allowing it to move down stream creating additional blockages.
An objective of the present invention is to provide an atherectomy catheter which is insertable and advancable in an artery over a flexible guide-wire. The flexible catheter is equipped with a coring means at its distal end to core and extract obstruction material and create a smooth lumen without cracking the arterial wall. The catheter is slidable in an eccentrically biasing sleeve that defines the catheter's trajectory in the vessel in order to selectively aim the coring means into the obstruction. This allows the treatment of eccentric lesions and the utilizing of the system in larger arteries without increasing the flexible catheter's diameter and the associated puncture wound at the point of insertion of the system into the vessel.
These and other objectives of the invention will become apparent from the following discussion and the accompanying drawings.